In vehicular applications, a typical four-wheel steering system steers the front and the rear wheels of a vehicle. The four-wheel steering system includes a front wheel steering system for steering a set of front wheels and a rear wheel steering system for steering a set of rear wheels. The rear wheel steering system utilizes a motor that induces movement of the rear wheels about vertical wheel axes.
However, a speed of the motor and a resulting speed that the rear wheels are moved about the wheel axes, can be limited by the voltage supplied by a voltage source to the motor. Thus, when a commanded voltage for a motor is greater than that which can be supplied by the voltage source, the motor moves the rear wheels at a speed limited by the voltage supplied by the voltage source to the motor.
Thus, there is a need for a rear wheel steering system that can increase a speed at which a motor moves the rear wheels of a vehicle at a desired torque.